tech-guru-tips: Automation / PLC

Showing posts with label Automation / PLC. Show all posts

Thursday, August 16, 2012

Data Acquisition System Components

A data acquisition system is designed to collect relevant measurement data for characterization, monitoring or control. The defined parameters of an application will determine the resolution, correctness, channel count and speed needs for a data acquisition system. There are a wide range of data acquisition systems and solutions available on the market. When implementing a data acquisition system, a detailed application requirement regarding capability and performance should be in place. The data acquisition system components are composed of devices, boards and equipment which gather data from external instruments and transforms the data into an analogue or digital (A/D) form for potential processing or signal conditioning.

Measurement Hardware

The most basic element of a data acquisition system is A/D Converter, which is used to convert DC voltages gained from the transducers into digital data. The gauged voltages may be equivalent to a certain temperature, pressure, flow or speed. Digital Input is another element of a data acquisition system which detects a digital bit pattern to examine whether an external device is on or off. Counter can be utilized to count incidents stemming from an external device. For instance, a counter card can be used to count the number of digital pulses.

Control Hardware
A D/A converter conducts the opposite functionality of an aforementioned A/D device. A D/A converter translates commands from the control hardware and transforms them into matching DC voltage or current. A Digital Output is another control hardware which receives commands from the control hardware and transforms them into a relevant digital bit pattern. The control switching card is used to provide power to external fans, pumps or valves through fulfilling an electrical circuit.

Switching

Electromechanical switches, including reed and armature relays, are important components in low-speed applications. A primary advantage is their capability to switch high-voltage and current levels; however, they are confined to switching rates of several hundred channels per second while electronic switches are utilized in high-speed applications. Multiplexer Configuration is mainly used for signal switching to a single measuring device. Normally, in the multiplexer configuration, only one signal is associated each time to the measuring device and the switching is break-before-make.

Signal Conditioning

This component is to magnify, attenuate, shape or segregate signals from transducers before they are transferred to the measurement hardware. Signal conditioning transforms the signal to a form which is better gauged by the system, or improves the chances of being measured. Transducers are instruments which convert physical parameters into electrical variables. The electrical variables are measured and the consequences are converted to engineering units.

Computer and Software

The computer can transfer data and store data for the data acquisition system while software enables communication between the computer and the hardware. Software can enable one to set the sampling rate of a board and obtain a predefined volume of data.

Add to Cart View detail

Data Acquisition System Tutorial

Data acquisition involves collecting signals from sources of measurement, storing them in digital format and presenting them on a PC. Choose from several technologies for data acquisition on personal computers, such as PCI, PCI Express, PXI, PXI Express, PCMCIA, USB, wireless and Ethernet. Automate the recording and measurement of data, and feed it to data analysis applications. Build a basic data acquisition system using transducers, sensors, signals, signal conditioning equipment, data acquisition hardware, device driver software and application software.

Instructions

1. Select a measuring instrument called a transducer to measure phenomena such as the room temperature, intensity of a light source or force applied to an object. For example, obtain a thermocouple or thermistor to measure temperature; or use a photo sensor to measure light intensity.

2. Find out the requirements of the transducer to convert the physical phenomenon into a measurable signal. Signals are classified as analog and digital signals. Analog signals take any value in a continuous range whereas digital signals take distinct values only. Voltage, temperature, pressure and sound are analog signals with the following characteristics: level or amplitude, shape (such as sine, cosine or sawtooth waves) and frequency. Each of these attributes can be measured on the transducer. Digital signals take two values, a low and a high. The low and high values are defined by a certain value of the phenomenon. Learn to measure the rate of a digital signal, or how many times the signal transitions between low and high within a unit of time, using your transducer screen.

3. Learn to select appropriate hardware for signal conditioning. Connecting the transducer to the data acquisition device may be too dangerous or not give accurate results. Use signal conditioning equipment, such as an amplifier, to smooth out the signal amplitude. You may also use a multiplexer to multiplex the signal with other signals. Multiplexing is a technique where two or more signals are sent over the same transferring line turn by turn.

4. Select data acquisition hardware. This is the equipment that interfaces between the computer and the incoming signals. Connect the transducer or signal conditioning hardware to the data acquisition hardware following the instructions in the user manual. Data acquisition devices provide analog and digital input or output, counters, timers or a combination of these functions. Familiarize yourself with the available data acquisition devices for the desktop computer platform.

5. Install the driver software for the data acquisition device using the instructions that came with the package. Device drivers are programs that communicate with the particular hardware device for which they are written; they provide an interface with the main computer.

6. Install the application software on your data acquisition platform computer. Buy a license for a vendor software package or have a team develop a custom-made program specifically tailored for the data. The application will store and process the digitized data.

Add to Cart View detail

Sunday, August 12, 2012

Identification and Control Equipment

Identification and control equipment is used to collect and communicate the information that is used to coordinate the flow of materials within a facility and between a facility and its suppliers and customers. The major types of identification and communication equipment are:

| Top |

1. Manual (No Equipment)

The identification of materials and associated communication can be performed manually with no specialized equipment

Although it is sometimes possible to manually coordinate the operation of a material handling system, it becomes more difficult to due so as the speed, size, and complexity of the system increases

| Top |

2. Bar Codes

Unique bar/space patterns represent various alphanumeric characters

Bar code system consists of bar code label, bar code scanner, and bar code printer

Contact bar code scanners use pen or wand to read labels

Noncontact bar code scanners include fixed beam, moving beam, and omnidirectional

1-D codes are most common; 2-D codes enable much greater data storage capability

| Top |

3. Radio Frequency (RF) Tag

Data encoded on chip encased in a tag

Noncontact: can be read when the tag is within 30 ft. of an antenna

Tags can either be attached to a container, or permanently or temporarily to an item

RF tags have greater data storage capability than bar codes

| Top |

4. Magnetic Stripe

Data encoded on a magnetic stripe that is readable in almost any environment

Requires contact with a reader

Greater storage capability and more expensive than bar codes

| Top |

5. Machine Vision

Does not require explicit encoding of data since objects can be identified by their physical appearance

Noncontact, but typically requires structured lighting

More flexible than other identification equipment, but less robust

| Top |

6. Portable Data Terminal

Handheld, arm-mounted, or vehicle-mounted data storage and communication device

Communicates with a host computer via a radio frequency or infrared link

Variety of input devices available: keyboard, bar code scanner, voice headset

| Top |

7. Electronic Data Interchange (EDI)/Internet

Electronic data interchange (EDI) provides standards for inter-corporate transfer of purchase orders, invoices, shipping notices, and other frequently used business documents

Prior to the Internet, EDI required expensive dedicated value added networks (VANs)

EDI is critical for implementing JIT manufacturing

| Top |

Add to Cart View detail

Storage Equipment

Storage equipment used for holding or buffering materials over a period of time. The major types of storage equipment are:

The most common reason for storing a product allows the other elements of production to operate more efficiently on a per-unit basis because the fixed costs associated with utilizing the element can be spread over more products; e.g., storing up to a truckload of product in a facility reduces the per-unit costs of shipping; and buffering or storage of WIP enables batch production which reduces the per-unit setup costs.

Other potential reasons for storage include: time bridging—allows product to be available when it is needed (e.g., storing spare machine parts at the facility); processing—for some products (e.g., wine), storage can be considered as a processing operation because the product undergoes a required change during storage; and securing—e.g., nuclear waste storage.

| Top |

1. Block Stacking (No Equipment)

Bulk storage using block stacking can result in the minimum cost of storage since cube utilization is high and no storage medium is required, but material accessibility is low since only the top of the front stack is accessible and loads at bottom of a stack must not require support

Storage racks are used when support and/or material accessibility is required

| Top |

2. Selective Pallet Rack

3. Drive-Through Rack

Loads are supported by rails attached to the upright beams

Lift trucks are driven between the uprights beams

Requires similar-width loads

Open at both ends, allowing access from both ends (FIFO)

| Top |

4. Drive-In Rack

Same as drive-through rack, except closed at one end, allowing entry from only one end (LIFO)

| Top |

5. Flow-Through Rack

Loads are supported on an incline to enable gravity-based movement of the loads within the rack (via, e.g., a gravity roller conveyor)

Loaded at the higher end and unloaded at the lower end (FIFO)

| Top |

6. Push-Back Rack

Same as push-back rack, except loaded and unloaded at the lower end and closed at the higher end (LIFO)

| Top |

7. Sliding Rack

Only one mobile aisle is used to access several rows of racks

Location of the aisle is changed by sliding the rows of racks along guide rails in the floor

Typically found in library stacks

| Top |

8. Cantilever Rack

Loads are supported by cantilever "arms"

Used to store long loads (e.g., bar stock, pipes, lumber)

Similar to pallet racks, except the front upright beams and the front supporting beams are eliminated

| Top |

9. Stacking Frame

Interlocking units that enable stacking of a load so that crushing does not occur

Can be disassembled and stored compactly when not in used

Pallet frames can be used to enable multilevel block stacking

| Top |

10. Shelves/Bins/Drawers

| Top |

11. Storage Carousel

Carousel consists of a set of vertically or horizontally revolving storage baskets or bins

Materials (and the storage medium) move to the operator, "part-to-man," for end-of-aisle picking

Each level of the carousel can rotate independently in a clockwise or counter-clockwise direction

Control ranges from manually activated push buttons to automated computer controlled systems

Provides an alternative to typical "man-to-part" AS/RS, where the S/R machine moves to the part

Similar to a trolley conveyor with storage baskets

| Top |

12. Automatic Storage/Retrieval Systems (AS/RS)

Consists of an integrated computer-controlled system that combines the storage medium, transport mechanism, and controls with various levels of automation for fast and accurate random storage of products and materials

Storage/retrieval (S/R) machine in an AS/RS operates in narrow aisle, serving rack slots on both sides of aisle; can travel in horizontal (along the aisle) and vertical (up and down a rack) directions at same time

Advantages: fewer material handlers, better material control (including security), and more efficient use of storage space

Disadvantages: high capital and maintenance costs, and difficult to modify

12(a) Unit Load AS/RS

Used to store/retrieve loads that are palletized or unitized and weigh over 500 lbs.

Stacking heights up to 130 ft. high, with most ranging from 60 to 85 ft. high; 5 to 6 ft. wide aisles; single- or double-deep storage racks

12(b) Miniload AS/RS

Used to store/retrieve small parts and tools that can be stored in a storage bin or drawer

End-of-aisle order picking and replenishment

Stacking heights range from 12 to 20 ft.; bin capacities range from 200 to 750 lbs.

Termed a "microload AS/RS" when used in assembly, kitting, and testing operations to deliver small containers of parts to individual workstations, where workstations are typically located on the sides of a pair of racks and the S/R machine operates between the racks to move containers to openings in the racks (storage lanes) located next to each station

12(c) Man-On-Board AS/RS

Used for in-aisle picking; operator picks from shelves, bins, or drawers within the storage structure

Manual or automatic control

S/R machine is similar to an order picker or turret truck and can sometimes operate as an industrial truck when outside an aisle, except the S/R is guided along a rail when operating in an aisle

12(d) Deep-Lane AS/RS

Similar to unit load AS/RS, except loads can be stored to greater depths in the storage rack

A rack-entry vehicle is used to carry loads into the racks from the S/R machine, and is controlled by the S/R machine

Termed an "automated item retrieval system" when used to automatically retrieve individual items or cases, with replenishment (storage) taking place manually from the rear of a flow-through storage lane and items are pushed forward with a rear-mounted pusher bar for automatic picking from the front of the storage lane

| Top |

13. Split-Case Order Picking System

Unlike an AS/RS, a split-case order picking system enables fully automated picking of individual items

Two general categories of split-case order picking system are robotic based systems and magazine/dispenser based systems

Robotic based systems are similar in construction to robotic pick and place palletizers

Magazine/dispenser based systems are similar to vending machines, but larger in scale

"A-Frame" dispenser system (pictured) is popular within pharmaceutical distribution centers; items are dispensed onto a belt conveyor that carries them into a container

| Top |

14. Mezzanine

Inexpensive means of providing additional storage or office space

Makes use of clear space over activities not requiring much headroom (e.g., restrooms, block storage, etc.)

At least 14 ft. of clear space is needed for a mezzanine

| Top |

Add to Cart View detail

Unit Load Formation Equipment

Unit load formation equipment used to restrict materials so that they maintain their integrity when handled a single load during transport and for storage. The major types of unit load formation equipment are ([+] = more info):

Advantages of unit loads:

More items can be handled at the same time, thereby reducing the number of trips required and, potentially, reducing handling costs, loading and unloading times, and product damage.
Enables the use of standardized material handling equipment.

Disadvantages of unit loads:

Time spent forming and breaking down the unit load.
Cost of containers/pallets and other load restraining materials used in the unit load
Empty containers/pallets may need to be returned to their point of origin.

| Top |

1. Self-Restraining (No Equipment)

One or more items that can maintain their integrity when handled as a single item (e.g., a single part or interlocking parts)

| Top |

2. Pallets

Platform with enough clearance beneath its top surface (or face) to enable the insertion of forks for subsequent lifting purposes

Materials: Wood (most common), paper, plastic, rubber, and metal

Size of pallet is specified by its depth (i.e., length of its stringers or stringer boards) and its width (i.e., length its deckboards)—pallet height (typically 5 in.) is usually not specified; orientation of stringers relative to deckboards of pallet is specified by always listing its depth first and width last: Depth (stringer length) x Width (deckboard length)

48 x 40 in. pallet is most popular in US (27% of all pallets—no other size over 5%) because its compatibility with railcar and truck trailer dimensions

1200 x 800 mm "Euro-Pallet" is the standard pallet in Europe

| Top |

3. Skids

Platform (typically metal) with enough clearance beneath its top surface to enable a platform truck to move underneath for subsequent lifting purposes

Forks can also be used to handle skids since the clearance of a skid is greater than that of a pallet

Compared to a pallet, a skid is usually used for heavier loads and when stacking is not required; a metal skid can lift heavier loads than an equal-weight metal pallet because it enables a platform truck to be used for the lifting, with the platform providing a greater lifting surface to support the skid as compared to the forks used to support the pallet

| Top |

4. Slipsheets

Thick piece of paper, corrugated fiber, or plastic upon which a load is placed

Handling method: tabs on the sheet are grabbed by a special push/pull lift truck attachment

Advantages: usually used in place of a pallet for long-distance shipping because their cost is 10–30% of pallet costs and their weight and volume is 1–5% of a pallet

Disadvantages: slower handling as compared to pallets; greater load damage within the facility; special lift truck attachment reduces the vehicle’s load capacity

| Top |

5. Tote Pans

Reusable container used to unitize and protect loose discrete items

Typically used for in-process handling

Returnable totes provide alternative to cartons for distribution

| Top |

6. Pallet Boxes/Skid Boxes

Reusable container used to unitize and protect loose items for fork/platform truck handling

| Top |

7. Bins/Baskets/Racks

Storage equipment that also can be used to unitize and protect loose discrete items

| Top |

8. Cartons

Disposable container used to unitize and protect loose discrete items

Typically used for distribution

Dimensions always specified as sequence: Length x Width x Depth, where length is the larger, and width is the smaller, of the two dimension of the open face of the carton, and depth is the distance perpendicular to the length and width

Large quantities of finished carton blanks or knocked-down cartons can be stored on pallets until needed

| Top |

9. Bags

Disposable container used to unitize and protect bulk materials

Typically used for distribution

Polymerized plastic ("poly") bags available from light weight (1 mil.) to heavy weight (6 mil.) in flat and gusseted styles

Dimensions of bag specified as: Width x Length, for flat bags, and Width x Depth (half gusset) x Length, for gusseted bags

| Top |

10. Bulk Load Containers

Reusable container used to unitize and protect bulk materials

Includes drums, cylinders, etc.

Used for both distribution and in-process handling

| Top |

11. Crates

Disposable container used to protect discrete items

Typically used for distribution

| Top |

12. Intermodal Containers

Reusable container used to unitize and protect loose discrete items

Enables a load to be handled as a single unit when it is transferred between road, rail, and sea modes of transport; e.g., the container can be unloaded from a cargo ship and loaded onto a truck as a single unit

It is not as common to use intermodal containers for airfreight transport because of aircraft shape and weight restrictions

The standard outside dimensions of intermodal containers are: 20 or 40 ft. in length; 8 ft. in width; and 8, 8.5, or 9.5 ft. in height; less 8 in. of length, 5 in. of width, and 9.5 in. of height to determine the inside dimensions. Typical sea transport costs per 40-ft container are: $3000–4000 from Japan to the US west coast, $4000–5000 from Singapore to the US west coast, and $2500–3500 from Europe to the US east coast; transport costs for a 20-ft. container is 70% of the costs of a 40-ft. container [15]

| Top |

13. Strapping/Tape/Glue

Used for load stabilization

Straps are either steel or plastic

Plastic strapping that shrinks is used to keep loads from becoming loose during shipment

| Top |

14. Shrink-Wrap/Stretch-Wrap

Used for load stabilization

In shrink-wrapping, a film or bag is placed over the load and then heat is applied to shrink the film or bag; allows irregular loads to be stabilized; manual or automatic; most shrink-wrap applications are being replaced by stretch-wrapping

In stretch-wrapping, a film is wound around the load while the film is stretched; allows irregular loads to be stabilized; manual or automatic; as compared to shrink-wrapping, stretch-wrapping has lower material, labor, and energy costs

| Top |

15. Palletizers

Used for load formation.

Three general methods of building (or "palletizing") unit loads:

15(a) Manual Palletizing

Operators arrange items into the desired pattern used to form the unit load

Since the ergonomics of loading and unloading are important (e.g., vertically, the prime working zone is between the knees and the chest; horizontally, reaches of more than 24 in. with a load should be avoided), lift and turn tables are often used

Semi-mechanized palletizers use operators to arrange items into the desired pattern for each layer of the unit load and a powered device is used to transfer layers onto a pallet and then lower the load for the next layer

15(b) Robotic Pick and Place Palletizers

Fully automated device to build unit loads

Used when flexibility is required (e.g., the "Distributor’s Pallet Loading Problem")

Greatest limitation is capacity, typically 6 cycles per minute; capacity is determined by the number of items handled with each pick operation

Operators arrange items into the desired pattern for each layer of the unit load and a powered device is used to transfer layers onto a pallet and then lower the load for the next layer

15(c) Conventional Stripper Plate Palletizers

Fully automated device to build unit loads

Used when high throughput of identical loads is required (e.g., the "Manufacturer’s Pallet Loading Problem")

Capacity is typically greater (30–180 items per minute) than pick and place because an entire layer is placed on the load at one time; not as flexible as pick and place

Preformed layer of items (cases) are indexed onto the stripper plate (or apron); when properly positioned over the pallet, the apron is pulled out from underneath the layer to deposit the layer onto the pallet

"In-line" pattern formation (top picture)—flexible patterns are not possible; ideal for high speed operation (up to 180 items per minute); takes up more room (larger machine) than right angle

"Right angle" pattern formation (bottom picture)—very flexible patterns are possible; can handle a wide variety of case sizes and types; limited capacity (up to 80 items per minute); compact design

| Top |

Add to Cart View detail

Positioning Equipment

Positioning equipment is used to handle material at a single location so that the material is in the correct position for subsequent handling, machining, transport, or storage. Unlike transport equipment, positioning equipment is usually used for handling at a single workplace. Material can also be positioned manually using no equipment. The major types of positioning equipment are:

As compared to manual handling, the use of positioning equipment can provide the following benefits [Modern Materials Handling, Sept. 1993]:

raise the productivity of each worker when the frequency of handling is high,
improve product quality and limit damage to materials and equipment when the item handled is heavy or awkward to hold and damage is likely through human error or inattention, and
reduce fatigue and injuries when the environment is hazardous or inaccessible.

| Top |

1. Manual (No Equipment)

Material can be positioned manually using no equipment

Under ideal circumstances, maximum recommended weight for manual lifting to avoid back injuries is 51 lbs.

Recommendation based on NIOSH (National Institute for Occupational Safety and Health) 1994 Lifting Equation, which uses six multipliers to reduce maximum recommended weight for less than ideal lifting tasks

| Top |

2. Lift/Tilt/Turn Table

Used when positioning involves the lifting, tilting, or turning of a load

Can be used to reduce or limit a worker’s lifting and/or reaching motions

Pallet load levelers are lift and turn tables used in manual palletizing to reduce the amount of bending and stooping involved with manually loading a pallet by combining a lifting and turning mechanism with a device that lowers the table as each layer is completed so that loading always takes place at the optimal height of 30 inches

| Top |

3. Dock Leveler

Used at loading docks to compensate for height differences between a truck bed and the dock

| Top |

4. Ball Transfer Table

Used in conveyor systems to permit manual transfer to and from machines and conveyors and between different sections of conveyors

Since loads are pushed on the table, ball friction limits the maximum load weight to 600 lbs.

| Top |

5. Rotary Index Table

Used for the synchronous transfer of small parts from station to station in a single workcenter

Circular table rotates in discrete intermittent steps to advance parts between stations located along its perimeter

Since each part moves between stations at the same time, it is difficult to put buffers between stations

Different from conveyors used as in-line indexing machines, where linear transfers can take place between multiple workcenters separated by long distances, since a rotary index table is restricted to circular transfers with a single compact workcenter

| Top |

6. Parts Feeder

Used for feeding and orienting small identical parts, particularly in automatic assembly operations [13]

Motion of parts in a random pile channeled so that each part automatically assumes a specified orientation, where the symmetries of a part define its possible orientations

Motion can be imparted through vibration, gravity, centrifugal force, tumbling, or air pressure

In a vibratory bowl feeder, the most versatile type of parts feeder, parts are dumped into a bowl and then move vibrate uphill along a track towards an outlet, where rejected parts fall off the track and are recycled

Parts feeders can be used to provide inspection capabilities with respect to the shape and weight of parts (e.g., the coin feeder of a vending machine)

| Top |

7. Air Film Device

Used to enable precision positioning of heavy loads

Sometimes referred to as "air pallets"

Can be used in place of cranes and hoists

Thin film of compressed (10–50 psi) air used to float loads of up to 300,000 lbs. so that a horizontal push of 1 lb. can move 1000 lb. load; floating action enables load to rotated or translated in any direction in the horizontal plane

Requires a smooth floor surface against which air streams underneath the device can push

Can be used in warehousing as the mechanism to convert stationary racks into sliding racks

| Top |

8. Hoist

Used for vertical translation (i.e., lifting and lowering) of loads

Frequently attached to cranes and monorails to provide vertical translation capability

Can be operated manually, electrically, or pneumatically

| Top |

9. Balancer

Mechanism used to support and control loads so that an operator need only guide a balanced ("weightless") load, thus providing precision positioning

Can also be attached to hoists and manipulators

| Top |

10. Manipulator

Used for vertical and horizontal translation and rotation of loads

Acting as "muscle multipliers," manipulators counterbalance the weight of a load so that an operator lifts a small portion (1%) of the load’s weight

Can be powered manually, electrically, or pneumatically

Manipulator’s end-effector can be equipped with mechanical grippers, vacuum grippers, electromechanical grippers, or other tooling

Manipulators fill the gap between hoists and industrial robots: they can be used for a wider range of positioning tasks than hoists and are more flexible than industrial robots due to their use of manual control

10(a) Rigid-Link Manipulator

Although similar in construction, a rigid-link manipulator is distinguished from an industrial robot by the use of an operator for control as opposed to automatic computer control

10(b) Articulated Jib Crane Manipulator

Extends a jib crane’s reaching capability in a work area through the use of additional links or "arms"

10(c) Vacuum Manipulator

Provides increased flexibility because rigid links are not used (vacuum, rigid-link, and articulated jib crane manipulators can all use vacuum gripper end-effectors)

| Top |

11. Industrial Robot

Used in positioning to provide variable programmed motions of loads

"Intelligent" industrial robots utilize sensory information for complex control actions, as opposed to simple repetitive "pick-and-place" motions

Industrial robots also used for parts fabrication, inspection, and assembly tasks

Consists of a chain of several rigid links connected in series by revolute or prismatic joints with one end of the chain attached to a supporting base and the other end free and equipped with an end-effector

Robot’s end-effector can be equipped with mechanical grippers, vacuum grippers, electromechanical grippers, welding heads, paint spray heads, or any other tooling

Although similar in construction, an industrial robot is distinguished from a manipulator by the use of programmed control logic as opposed manual control

Pick-and-place industrial robots used as automatic palletizers

Mobile robots similar in construction to free-ranging AGVs

Can be powered manually, electrically, or pneumatically

| Top |

Add to Cart View detail

Industrial Trucks

Industrial trucks are used to move materials over variable paths, with no restrictions on the area covered by the movement. The major types of industrial trucks are:

Industrial trucks:

Used to move materials over variable (horizontal) paths with no restrictions on the area covered (i.e., unrestricted area)
Provide vertical movement if the truck has lifting capabilities
Used when there is insufficient (or intermittent) flow volume such that the use of a conveyor cannot be justified
Provide more flexibility in movement than conveyors and cranes
Not licensed to travel on public roads—"commercial trucks" are licensed to travel on public roads

Characteristics:

Pallet/Non-Pallet: Does the truck have forks for handling pallets, or does the truck have a flat surface on which to place loads. Non-Pallet => (usually) other means required to load truck.

Manual/Powered: Does the truck have manual or powered vertical (lifting) and/or horizontal (travel) movement capabilities. Manual => walk => operator provides the force needed for lifting loads and/or pushing the vehicle. Powered => on-board power source (e.g., batteries) used for lifting and/or travel.

Walk/Ride: For non-automated trucks, can the operator ride on the truck (in either a standing or sitting position) or is the operator required to walk with the truck during travel. Walk => manual or powered travel possible => powered travel speed limited to a normal walking pace. Ride => powered => travel speed can be faster than a walking pace.

Stack/No Stack: Can the truck be used to lift loads for stacking purposes. Stack => can also be used as no stack => more expensive to add stacking capability. No Stack may lift a load a few inches to clear the floor for subsequent travel (e.g., pallet jack), but the loads cannot be stacked on top of each other or on shelves.

Narrow Aisle: Is the lift truck designed to have a small turning radius or does it not have to turn at all in an aisle when loading/unloading. Narrow Aisle => greater cost and (usually) standing operator => less aisle space required. Counterbalance and/or straddle used for load support. Small turning radius => load support via straddle or reaching capabilities. No turning required => even narrower aisle => only one-side loading (sideloaders) or the capability to rotate the load (turret truck).

Automated: Is the truck automated so that it can transport loads without requiring an operator. Non-Automated => direct labor cost of operator is by far the largest cost to operate a non-automated truck. Semi-Automated => operator used to control loading/unloading, but automated transport control (e.g., the S/R machine of a Man-on-board AS/RS). Automated => Automated Guided Vehicle (AGV) => no direct labor cost, but higher equipment costs.

| Top |

1. Hand Truck

Non-pallet + manual + no stack

1(a) Two-Wheeled Hand Truck

Load tilted during travel

1(b) Dolly

Three or more wheeled hand truck with a flat platform in which, since it has no handles, the load is used for pushing

1(c) Floor Hand Truck

Four or more wheeled hand truck with handles for pushing or hitches for pulling

Sometimes referred to as a "cart" or "(manual) platform truck"

| Top |

2. Pallet Jack

Pallet + walk + no stack

Front wheels are mounted inside the end of the forks and extend to the floor as the pallet is only lifted enough to clear the floor for subsequent travel

Pallet restrictions: reversible pallets cannot be used, double-faced nonreversible pallets cannot have deckboards where the front wheels extend to the floor, and enables only two-way entry into a four-way notched-stringer pallet because the forks cannot be inserted into the notches

2(a) Manual Pallet Jack

Pallet + walk + no stack + manual

Manual lifting and/or travel

2(b) Powered Pallet Jack

Pallet + walk + no stack + powered

Powered lifting and/or travel

| Top |

3. Walkie Stacker

Pallet + walk + stack

3(a) Manual Walkie Stacker

Pallet + walk + stack + manual

Manual lifting and/or travel (and straddle load support)

3(b) Powered Walkie Stacker

Pallet + walk + stack + powered

Powered lifting and/or travel (and either counterbalance or straddle load support)

| Top |

4. Pallet Truck

Pallet + ride + no stack

Same pallet restrictions as a pallet jack

Control handle typically tilts to allow operator to walk during loading/unloading

Powered pallet jack is sometimes referred to as a "(walkie) pallet truck"

| Top |

5. Platform Truck

Non-pallet + powered + no stack

Platform used to provide support for nonpalletized loads

Used for skid handling; platform can lift skid several inches to allow it to clear the floor

Greater lifting capacity compared to fork trucks because the platform provides a greater lifting surface to support a load

5(a) Walkie Platform Truck

Non-pallet + powered + no stack + walk

Operator walks next to truck

Floor hand truck is sometimes referred to as a "(manual) platform truck"

5(b) Rider Platform Truck

Non-pallet + powered + no stack + ride

Operator can ride on truck

| Top |

6. Counterbalanced (CB) Lift Truck

Pallet + ride + stack

Also referred to as fork truck.

Weight of vehicle (and operator) behind the front wheels of truck counterbalances weight of the load (and weight of vehicle beyond front wheels); front wheels act as fulcrum or pivot point.

Rated capacity reduced for load centers greater than 24 in. and lift heights greater than 13 ft.

Workhorses of material handling because of their flexibility: indoor/outdoor operation over a variety of different surfaces; variety of load capacities available; and variety of attachments available—fork attachments can replace the forks (e.g., carton clamps) or enhance the capabilities of the forks (e.g., blades for slipsheets).

6(a) Sit-Down Counterbalanced Lift Truck

Operator sits down

12-13 ft. minimum aisle width requirement

6(b) Stand-Up Counterbalanced Lift Truck

Operator stands up, giving vehicle narrow-aisle capability

9-11 ft. minimum aisle width requirement

Faster loading/unloading time compared to NA straddle and reach trucks

| Top |

7. Narrow-Aisle (NA) Straddle Truck

Similar to stand-up CB lift truck, except outrigger arms straddle a load and are used to support the load instead of the counterbalance of the truck

7-8 ft. minimum aisle width requirement

Less expensive than stand-up CB lift truck and NA reach truck

Since the load is straddled during stacking, clearance between loads must be provided for the outrigger arms

Arm clearance typically provided through the use of load-on-beam rack storage or single-wing pallets for load-on-floor storage

| Top |

8. Narrow-Aisle (NA) Reach Truck

Similar to both stand-up CB lift truck and NA straddle truck

8-10 ft. minimum aisle width requirement

Load rests on the outrigger arms during transport, but a pantograph (scissors) mechanism is used for reaching, thereby eliminating the need to straddle the load during stacking

Reaching capability enables the use of shorter outrigger arms (arms > 1/2 load depth) as compared to NA straddle truck (arms = load depth)

Counterbalance of the truck used to support the load when it extends beyond the outrigger arms

Although the NA reach truck requires slightly wider aisles than a NA straddle truck since its outrigger arms do not enter a rack during storage, it does not require arm clearance between loads (arm clearance is still required when the truck must enter a storage lane when block stacking or drive-in or -through racks are used)

Extended reaching mechanisms are available to enable double-deep storage

| Top |

9. Turret Truck

Greater stacking height compared to other narrow-aisle trucks (40 ft. vs. 25 ft.), but greater investment cost

Forks rotate to allow for side loading and, since truck itself does not rotate during stacking, the body of the truck can be longer to increase its counterbalance capability and to allow the operator to sit

Can function like a sideloader for transporting greater-than-pallet-size load

9(a) Operator-Down Turret Truck

Operator not lifted with the load

5-6 ft. minimum aisle width requirement

Termed a swingmast truck (picture shown) when, instead of just the forks, the entire mast rotates (thus can store on only one side of a aisle while in aisle)

9(b) Operator-Up Turret Truck

Operator lifted with the load to allow precise stacking and picking

5-7 ft. minimum aisle width requirement

| Top |

10. Order Picker

Similar to NA straddle truck, except operator lifted with the load to allow for less-than-unit-load picking

Typically has forks to allow the truck to be used for pallet stacking and to support a pallet during less-than-pallet-load picking

"Belly switch" used for operator safety during picking

| Top |

11. Sideloader

Forks mounted perpendicular to direction of travel to allow for side loading and straddle load support

5-6 ft. minimum aisle width requirement

Can be used to handle greater-than-pallet-size loads (e.g., bar stock)

| Top |

12. Tractor-Trailer

Non-load-carrying tractor used to pull a train of trailers (i.e., dollies or floor hand trucks)

Extends the transporting capacity of floor hand trucks

Typically used at airports for baggage handling

| Top |

13. Personnel and Burden Carrier

Non-load-carrying vehicle used to transport personnel within a facility (e.g., golf cart, bicycle, etc.)

| Top |

14. Automatic Guided Vehicle (AGV)

AGVs do not require an operator

Good for high labor cost, hazardous, or environmentally sensitive conditions (e.g., clean-room)

Also termed "automated" guided vehicle

AGVs good for low-to-medium volume medium-to-long distance random material flow operations (e.g., transport between work cells in a flexible manufacturing system (FMS) environment)

Two means of guidance can be used for AGV systems:

Fixed path: Physical guidepath (e.g., wire, tape, paint) on the floor used for guidance
Free-ranging: No physical guidepath, thus easier to change vehicle path (in software), but absolute position estimates (from, e.g., lasers) are needed to correct dead-reckoning error

14(a) Tow AGV

Used to pull a train of trailers

Automated version of a tractor trailer

Trailers usually loaded manually (early type of AGV, not much used today)

14(b) Unit Load AGV

Have decks that can be loaded manually or automatically

Deck can include conveyor or lift/lower mechanism for automatic loading

Typically 4 by 4 feet and can carry 1–2,000 lb. loads

Typically less than 10 vehicles in AGV system

14(c) Assembly AGV

Used as assembly platforms (e.g., car chassis, engines, appliances)

Greatest development activity during the 1980s (alternative to AEMs)

Typically 50–100 vehicles in AGV system

14(d) Light Load AGV

Used for small loads (< 500 lbs), e.g., components, tools

Typically used in electronics assembly and office environments (as mail and snack carriers)

14(e) Fork AGV

Counterbalanced, narrow-aisle straddle, and sideloading versions available

Typically have sensors on forks (e.g., infrared sensors) for pallet interfacing

| Top |

Add to Cart View detail

Total Items:
SubTotal:
Tax Cost:
Shipping Cost:
Final Total:

Shopping Cart

logo

Labels

Thursday, August 16, 2012

Data Acquisition System Components

Data Acquisition System Tutorial

Sunday, August 12, 2012

Identification and Control Equipment

1. Manual (No Equipment)

2. Bar Codes

3. Radio Frequency (RF) Tag

4. Magnetic Stripe

5. Machine Vision

6. Portable Data Terminal

7. Electronic Data Interchange (EDI)/Internet

Storage Equipment

1. Block Stacking (No Equipment)

2. Selective Pallet Rack

3. Drive-Through Rack

4. Drive-In Rack

5. Flow-Through Rack

6. Push-Back Rack

7. Sliding Rack

8. Cantilever Rack

9. Stacking Frame

10. Shelves/Bins/Drawers

11. Storage Carousel

12. Automatic Storage/Retrieval Systems (AS/RS)

12(a) Unit Load AS/RS

12(b) Miniload AS/RS

12(c) Man-On-Board AS/RS

12(d) Deep-Lane AS/RS

13. Split-Case Order Picking System

14. Mezzanine

Unit Load Formation Equipment

1. Self-Restraining (No Equipment)

2. Pallets

3. Skids

4. Slipsheets

5. Tote Pans

6. Pallet Boxes/Skid Boxes

7. Bins/Baskets/Racks

8. Cartons

9. Bags

10. Bulk Load Containers

11. Crates

12. Intermodal Containers

13. Strapping/Tape/Glue

14. Shrink-Wrap/Stretch-Wrap

15. Palletizers

15(a) Manual Palletizing

15(b) Robotic Pick and Place Palletizers

15(c) Conventional Stripper Plate Palletizers

Positioning Equipment

1. Manual (No Equipment)

2. Lift/Tilt/Turn Table

3. Dock Leveler

4. Ball Transfer Table

5. Rotary Index Table

6. Parts Feeder

7. Air Film Device

8. Hoist

9. Balancer

10. Manipulator

10(a) Rigid-Link Manipulator

10(b) Articulated Jib Crane Manipulator

10(c) Vacuum Manipulator

11. Industrial Robot

Industrial Trucks

1. Hand Truck

1(a) Two-Wheeled Hand Truck

1(b) Dolly

1(c) Floor Hand Truck

2. Pallet Jack

2(a) Manual Pallet Jack

2(b) Powered Pallet Jack

3. Walkie Stacker

3(a) Manual Walkie Stacker

3(b) Powered Walkie Stacker

4. Pallet Truck